This invention relates to an electrofluidic converter including a pressure fluid operated, bistable fluidic element having a pressure fluid supply inlet opening into an interaction chamber, two outlets extending downstream from the interaction chamber to the outside or exterior and diverging in direction at an acute angle, two control inlets commuicating with the interaction chamber, and a magnetic system actuated by electric input signals and influencing the control pressure in the control inlets to deviate the pressure fluid from one outlet to the other outlet.
Such electrofluidic converters are used, for example, in control circuits where the input quantity is an electric signal while the manipulated variable is a fluid signal. German OS No. 1,817,651 discloses an electrofluidic converter of the type mentioned which can be used in household appliances, such as washing or dish washing machines, as a directional water switch. The control conduits of the bistable, fluidic element, designed as a pure fluidic logic element, are closed alternately by means of an electromagnetically displaceable tongue. Due to the suction effect of the pressure fluid flowing through the bistable fluidic element, the pressure in the control inlet which is just closed is less than that in the open one so that, through the difference between the control pressures, the pressure fluid in the outlet associated with the closed control inlet is deviated.
However, in general, a switching operation produced by the suction effect of the bistable fluidic element is slower than one which is responsive to a pressure or power impulse rapidly transmitted in the control inlets. Thus, the limit frequency of this electrofluidic converter is relatively low and is further restricted by the inertia and the spring constant of the elastic tongue, as well as by the relatively large air gaps between the elastic tongue and the magnetic system.
Moreover, the limiting frequency of a control circuit comprising an electrofluidic converter is determined by the limiting frequency of the latter, even through the respective value of the electric part of the entire hybrid control circuitry may be relatively easily chosen very high. In order not to reduce the quality of the entire hybrid circuitry unnecessarily, an effort must be made to obtain a limiting frequency, of the electrofluidic converter, which is as high as possible. At the same time, the design of the electrofluidic converter should be such as to permit an operation with relatively feeble electric input signals.